JP2023014485A - stem holder - Google Patents

Abstract

To provide a stem holder suitable for holding a stem until bone cement hardens.SOLUTION: A stem holder 2 comprises: a rod 4 including a distal end 41 to be inserted in a hole 14 provided on a shoulder part 12 of a stem 1, and a proximal end 42 opposite to the distal end 41; a sleeve 3 penetrated into the rod 4; and an arm 6 attached to the sleeve 3 and including a holding hole 60 for inserting a neck part 13 of the stem 1. The sleeve 3 includes a female thread 33 formed on an inner peripheral surface thereof, and the rod 4 includes a male thread 43 to be threadedly engaged with the female thread 33 formed thereon. The rod 4 includes a knob 5 at the proximal end 42.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a stem holder used for artificial hip joint replacement surgery.

In artificial hip joint replacement, the neck of the femur is first resected, and then an insertion hole for the stem of the artificial hip joint is machined in the femur. The stem includes a body portion that is embedded in the femur, a neck portion to which the femoral head ball is attached, and a shoulder portion located between the body portion and the neck portion (see, for example, Patent Document 1).

WO2015/098727

Methods for fixing the stem to the femur include methods using bone cement and methods using no bone cement. When bone cement is used, it is necessary to inject the bone cement into the insertion hole of the femur, insert the stem, and hold the stem until the bone cement hardens.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stem holder suitable for holding a stem until the bone cement hardens.

In order to solve the above problems, the present invention provides a stem holder used to hold a stem until bone cement hardens, the distal end inserted into a hole provided in the shoulder of the stem; a rod having a proximal end opposite to a distal end; a sleeve passed through the rod; and an arm attached to the sleeve and having a retaining hole into which the neck portion of the stem is inserted; A stem holder is provided in which a female thread is formed on the inner peripheral surface, a male thread is formed on the rod to be screwed with the female thread, and a knob is attached to the end of the rod.

According to the above configuration, when the knob is rotated in the direction in which the rod advances while the neck portion of the stem is inserted into the holding hole, the distal end of the rod is inserted into the hole in the shoulder portion of the stem. Furthermore, by rotating the knob until the rod cannot move forward, the stem can be firmly fixed to the stem holder. Therefore, it is possible to realize a stem holder suitable for holding the stem until the bone cement hardens.

For example, the sleeve includes a shaft on the distal end side of the rod and a grip on the proximal end side of the rod, the arm is attached to the shaft, and the female groove is formed on the inner peripheral surface of the grip. good.

A male thread is formed on the outer peripheral surface of the shaft, and a ring fixed to the tip of the shaft; The arm may be provided with a groove into which the shaft is inserted, and the arm may be attached to the shaft by being pressed against the ring by the fixing member. With this configuration, the arm can be easily replaced according to the size of the stem.

The present invention provides a stem holder suitable for holding a stem until the bone cement hardens.

1 is a perspective view of a stem holder according to one embodiment of the invention; FIG. Fig. 3 is a perspective view of a stem; FIG. 4 is a cross-sectional view of a state in which a stem is held by a stem holder; Fig. 10 is a perspective view of the distal end of the stem holder with the arm removed; FIG. 3 is a perspective view of an arm; It is a perspective view of the arm of a modification.

FIG. 1 shows a stem holder 2 according to one embodiment of the present invention, and FIG. 2 shows a stem 1 held by the stem holder 2. As shown in FIG. A stem holder 2 is used to hold the stem 1 until the bone cement hardens.

The stem 1 includes a body portion 11 to be implanted in the femur, a neck portion 13 to which the femoral head ball is attached, and a shoulder portion 12 positioned between the body portion 11 and the neck portion 13 . The body portion 11 extends downward from the shoulder portion 12 and the neck portion 13 extends obliquely upward from the shoulder portion 12 when the axial direction of the femur is defined as the vertical direction.

The main body portion 11 has a shape in which the width of the plane on which the main body portion 11 and the neck portion 13 are arranged decreases downward. The shoulder portion 12 is provided with a hole 14 that opens upward.

The stem holder 2 includes a rod 4 and a sleeve 3 passed through the rod 4, as shown in FIG. Rod 4 has a distal end 41 that is inserted into hole 14 in shoulder 12 of stem 1 and a proximal end 42 opposite distal end 41 . A distal end 41 and a proximal end 42 overhang the sleeve 3 . The distal end 41 is tapered to a point, the maximum diameter of the distal end 41 being larger than the diameter of the hole 14 and the minimum diameter of the distal end 41 being smaller than the diameter of the hole 14 .

The sleeve 3 includes a shaft 31 on the distal end 41 side of the rod 4 and a grip 32 on the proximal end 42 side of the rod 4 . The outer diameter of the grip 32 is thicker than the outer diameter of the shaft 31 . The grip 32 is the part that is gripped by the user.

In the present embodiment, the outer peripheral surface of the grip 32 forms a hexagonal prism, but the shape of the grip 32 is not limited to this, and the outer peripheral surface of the grip 32 may form a cylinder.

The shaft 31 and the grip 32 are connected with each other. In this embodiment, the end of the shaft 31 on the side of the grip 32 is fitted into the end of the grip 32 on the side of the shaft 31 .

A female thread 33 is formed on the inner peripheral surface of the end portion of the grip 32 on the base end 42 side of the rod 4 . On the other hand, a male thread 43 to be screwed with the female thread 33 is formed in a portion near the proximal end 42 of the rod 4 .

A knob 5 is attached to the proximal end 42 of the rod 4 . In the present embodiment, the knob 5 has a substantially disk shape with a diameter larger than the outer diameter of the grip 32, but the shape and size of the knob 5 are not limited to this, and can be changed as appropriate.

An arm 6 is attached to the shaft 31 . Arm 6 has a retaining hole 60 into which neck 13 of stem 1 is inserted.

More specifically, the arm 6 includes a tubular body 61 forming a holding hole 60 and a bracket 62 supporting the tubular body 61 . The bracket 62 extends from the shaft 31 in a direction perpendicular to the axial direction of the shaft 31 and then bends obliquely toward the distal end 41 of the rod 4 . An end of the bracket 62 is provided with a fitting hole 64 into which the tubular body 61 is fitted.

As shown in FIG. 5, the proximal end of the bracket 62 is provided with a groove 63 that opens toward the side opposite to the distal end. The shaft 31 is inserted into this groove 63 . The shaft 31 has a flat surface 35 on its outer peripheral surface, as shown in FIG. One side surface of the groove 63 of the bracket 62 is a flat surface 65 , and the flat surface 65 is in surface contact with the flat surface 35 of the shaft 31 , thereby restraining the relative rotation of the arm 6 with respect to the shaft 31 .

Furthermore, in this embodiment, the ring 7 and the fixing member 8 are arranged on both sides of the bracket 62 . Ring 7 is fixed to the tip of shaft 31 .

A circumferentially continuous groove is formed on the outer peripheral surface of the tip of the shaft 31 . The ring 7 has a protrusion on its inner peripheral surface that fits into the groove. Further, the ring 7 is divided into a pair of halves, as shown in FIG. be done.

As shown in FIG. 5, the bracket 62 is formed with a substantially C-shaped depression 66 surrounding the groove 63 described above. An end portion of the ring 7 on the bracket 62 side is fitted into the recess 66 .

The fixing member 8 is tubular. By fixing the ring 7 to the tip of the shaft 31 as described above, the fixing member 8 is prevented from falling off from the shaft 31 . As shown in FIG. 3, a female thread 81 is formed on the inner peripheral surface of the end portion of the fixing member 8 opposite to the bracket 62 . On the other hand, a male thread 34 is formed on the outer peripheral surface of the shaft 31 to be screwed with the female thread 81 .

When the fixing member 8 is rotated in the direction in which the fixing member 8 advances with the shaft 31 inserted into the groove 63 of the bracket 62 , the bracket 62 is pressed against the ring 7 by the fixing member 8 . The arm 6 is thereby attached to the shaft 31 . As described above, since the bracket 62 side end of the ring 7 is fitted in the recess 66, the arm 6 is prevented from falling off the shaft 31 even if the fixing member 8 is slightly loosened.

In the stem holder 2 configured as described above, when the knob 5 is rotated in the direction in which the rod 4 advances with the neck portion 13 of the stem 1 inserted into the holding hole 60 , the distal end 41 of the rod 4 is pushed into the shoulder of the stem 1 . It is inserted into hole 14 of portion 12 . Furthermore, the stem 1 can be firmly fixed to the stem holder 2 by rotating the knob 5 until the forward movement of the rod 4 becomes impossible. Therefore, it is possible to realize a stem holder 2 suitable for holding the stem 1 until the bone cement hardens.

Further, in this embodiment, the arm 6 is attached to the shaft 31 by pressing the bracket 62 against the ring 7 by the fixing member 8 , so that the end of the ring 7 can be moved from the recess 66 to the fixing member 8 by loosening the fixing member 8 . By releasing the fitting, the arm 6 can be easily replaced according to the size of the stem 1.例文帳に追加

(Modification)
The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.

For example, the attachment of the arm 6 to the shaft 31 does not necessarily require the use of the ring 7 and the fixing member 8 . As an alternative means, the bracket 62 of the arm 6 is provided with a through hole opening to the groove 63, a female thread is formed on the inner peripheral surface of the through hole, and the arm 6 is attached to the shaft by using a threaded knob that is screwed into the female thread. 31 may be fixed.

Furthermore, the arm 6 does not necessarily have to be replaced according to the size of the stem 1. For example, like the arm 6A of the modified example shown in FIG.

1 Stem 11 Body 12 Shoulder 13 Neck 14 Hole 2 Stem Holder 3 Sleeve 31 Shaft 32 Grip 33 Female Thread 34 Male Thread 4 Rod 41 Distal 42 Base 43 Male Thread 5 Knob 6 Arm 60 Holding Hole 63 Groove 7 Ring 8 Fixing Member 81 internal thread

Claims (3)

A stem holder used to hold a stem until the bone cement hardens, comprising:
a rod having a distal end inserted into a hole provided in a shoulder of the stem and a proximal end opposite the distal end;
a sleeve penetrated by the rod;
an arm attached to the sleeve and having a retaining hole into which the neck of the stem is inserted;
A female thread is formed on the inner peripheral surface of the sleeve,
The rod is formed with a male thread that screws together with the female thread,
A stem holder, wherein a knob is attached to the end of the rod. The sleeve includes a shaft on the distal end side of the rod and a grip on the proximal end side of the rod, the arm is attached to the shaft, and the female groove is formed on the inner peripheral surface of the grip. Item 1. The stem holder according to item 1. A male thread is formed on the outer peripheral surface of the shaft,
a ring fixed to the tip of the shaft;
a cylindrical fixing member having an inner peripheral surface formed with a female thread that engages with the male thread;
The arm is provided with a groove into which the shaft is inserted,
3. The stem holder according to claim 2, wherein said arm is attached to said shaft by being pressed against said ring by said fixing member.

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